Topic Contents

Fetal Hydantoin Syndrome

National Organization for Rare Disorders, Inc.

ImportantIt is possible that the main title of the report Fetal Hydantoin Syndrome is not the name you expected.

Disorder Subdivisions

None

General Discussion

SummaryFetal hydantoin syndrome is a characteristic pattern of mental and physical birth defects that results from maternal use of the anti-seizure (anticonvulsant) drug phenytoin (Dilantin) during pregnancy. The range and severity of associated abnormalities will vary greatly from one infant to another. However, characteristic features may include distinctive skull and facial features, growth deficiencies, underdeveloped (hypoplastic) nails of the fingers and toes, and/or mild developmental delays. Other findings occasionally associated with this syndrome include cleft lip and palate, a head circumference that is smaller than would be expected based upon an infant's age and gender (microcephaly), and skeletal malformations particularly of the fingers or hands. The exact risk of a fetus developing fetal hydantoin syndrome is not fully understood, but only approximately 5-10% of fetuses exposed to phenytoin develop the disorder.

IntroductionAnti-seizure medications, also known as antiepileptic or anticonvulsant medications are among the most common teratogens prescribed to women of childbearing age. A teratogen is a drug that interferes with the development of a fetus. Affected infants often develop similar symptoms regardless of the associated drug, particularly symptoms affecting the head and face region (craniofacial abnormalities). Studies have indicated that fetal valproate syndrome is associated with greater risk of neurological and cognitive abnormalities than other anti-seizure medications. NORD has a separate report on fetal valproate syndrome.Although some disorders due to specific drugs (e.g. fetal hydantoin syndrome) are rare, many researchers believe that when considering the teratogenic effects of all antiepileptic drugs collectively these disorders are not rare. The concept of fetal antiepileptic syndromes in this regard is less useful than in the past and the broad consideration of the major and minor congenital malformations, various cognitive impairments, and behavioral abnormalities taken as a broader, collective concept is more appropriate.

Supporting Organizations

American Cleft Palate-Craniofacial Association

1504 East Franklin Street

Suite 102

Chapel Hill, NC 27514-2820

USA

Tel: (919)933-9044

Fax: (919)933-9604

Tel: (800)242-5338

Email: info@cleftline.org

Website: http://www.cleftline.org

Cleft Lip and Palate Foundation of Smiles

2044 Michael Ave SW

Wyoming, MI 49509

Tel: (616)329-1335

Email: Rachel@cleftsmile.org

Website: http://www.cleftsmile.org

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

Website: http://rarediseases.info.nih.gov/GARD/

March of Dimes

1275 Mamaroneck Avenue

White Plains, NY 10605

Tel: (914)997-4488

Fax: (914)997-4763

Email: AskUs@marchofdimes.org or preguntas@nacersano.org

Website: http://www.marchofdimes.org and nacersano.org

Organisation For Anti-Convulsant Syndrome

23 Morriston Close

South Oxhey

Watford, WD196UB

United Kingdom

Tel: 4402083869271

Email: OACSsecretary@gmail.com

Website: http://www.oacscharity.org

The Arc

1825 K Street NW, Suite 1200

Washington, DC 20006

Tel: (202)534-3700

Fax: (202)534-3731

Tel: (800)433-5255

Email: info@thearc.org

Website: http://www.thearc.org

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated: 7/6/2015Copyright 2015 National Organization for Rare Disorders, Inc.

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